AB0995 Metabolic phenotype of knee osteoarthritis: characteristic biochemical and imaging features
Authors: E. Taskina, L. Alekseeva, N. Kashevarova, K. Telyshev, D. Kudinsky, N. Demin, O. Alekseeva, M. Cherkasova, E. Samarkina, E. Strebkova, E. Sharapova, F. Bibulatova, O. Tenkova, A. Aboleshina, E. Kharlamova, T. Raskina, J. Averkieva, E. Usova, I. Vinogradova, O. Salnikova, E. Otteva, A. Lila
Journal: Annals of the Rheumatic Diseases (2022)

Objectives to outline specific biochemical and imaging features of metabolic phenotype of knee osteoarthritis (OA) in a multicenter prospective study. Methods 284 female patients with knee OA (according to the ACR criteria) aged 40-78 were included in this prospective multicenter study. OA radiologic stages in the study group varied from I to III (Kellgren &amp; Lawrence) and all the patients signed an informed consent. Mean age was 58.5 ± 9.5 years, disease duration was 5 (2-10) years. BMI was 29.6 ± 5.6 kg/m 2 , with hip (HC) – 109.3 ± 10.4 cm and waist circumference (WC) – 92.5 ± 12.5 cm. Physicians filled out individual case report forms, which included anthropometric information, history and physical assessment data. All patients performed lab tests, ultrasonography and x-ray of the knee, as well as proximal femur and lumbar spine DEXA. Results Metabolic phenotype was diagnosed in 52.4% of patients. Participants were then divided in two groups. Patients with metabolic phenotype of osteoarthritis were older (61 (57-68) vs 52 (43-58), respectively, p&lt;0.0001), had higher BMI (31.6 (28.6-35.4) vs 26.4 (23.4-30.3), p&lt;0.0001) and had more intense VAS knee pain while walking on flat surface (50 (40-60) vs 35 (10-50), p&lt;0.0001). There were also statistically significant differences when we analyzed the imaging results (Table 1). Patients with metabolic phenotype of knee OA had higher chances of grade III K&amp;L (ОR=4.4, 95% CI 1.3-14.2, р=0.01) and more significant medial joint space narrowing, bigger tibial osteophytes; knee ultrasound revealed thinner cartilage and thicker synovium. DEXA showed higher total hip BMD. Patients with metabolic phenotype had higher levels of CRP, HbA1c, uric acid, cholesterol, LDL, triglycerides, ALT, AST, glucose, leptin and COMP. Table 1. Comparison of patients depending on phenotype Index Metabolic phenotype(n=149) No metabolic phenotype(n=135) p K&amp;L radiologic grade 0.01 I grade 13.6% 56.7% II grade 62.7% 36.7% III grade 23.7% 6.6% Posterior lateral tibial cartilage, mm, Me 1.5 (1.4-1.8) 1.7 [1.6;1.8] 0.05 Posterior medial tibial cartilage, mm, Me 1.6 (1.3-1.8) 1.7 [1.6;1.8] 0.014 Medial knee joint space, mm, Me 2.6 (1-4.6) 3.6 [3;4.3] 0.023 Osteophytes of the medial tibial condyle, mm, Me 1 (1-2) 0 [0;0] 0.025 Osteophytes of the lateral tibial condyle, mm, Me 1 (1-2) 0[0;1] 0.042 Synovium thickness, mm, Me 3.1 (2.9-3.5) 2.9 (2.6-3.1) 0.02 Total hip BMD, (g/cm 2 ), mm, Me 0.95 (0.87-1.02) 0.87 (0.77-0.99) 0.03 CRP, mg/l, Me 2.8 (1.4-5.1) 1.1 (0.49-2.0) 0.0001 HbA1c, %, Me 5.7 (5.4-5.9) 5.2 (4.9-5.6) 0.0001 Uric acid, mcmol/l, Me 312 (268-391) 269.7 (233.9-324.5) 0.0002 Cholesterol, mmol/l, Me 6.4 (5.33-6.85) 5.4 (4.78-5.82) 0.002 LDL, mmol/l, Me 4 (3.38-4.59) 3.1 (2.6-3.89) 0.0009 Triglycerides, mmol/l, Me 1.6 (1.19-2.44) 1.1 (0.76-1.48) &lt;0.0001 ALT/AST, units/l, Me 21 (17.15-28.9)/ 20.6 (17.6-25) 15.9 (11.4-19.8)/ 18.1(14.9-21.6) 0.0006 Glucose, mmol/l, Me 5.6 (5.1-6,155) 5.2 (4.97-5.53) 0.001 Leptin, ng/ml, Me 35.6 (25.5-55.6) 20 (14.7-31) &lt;0.001 COMP, ng/ml, Me 1415 (1115-2100) 712.2 (484.5-1015) &lt;0.001 IL-6, pg/ml, Me 0.55 (0.25-0.8) 0.03 (0.01-0.4) &lt;0.005 Spearman correlation analysis showed positive correlations (p &lt;0.05) between the metabolic phenotype and OA radiologic stage (r=0.44), size of tibial osteophytes (r=0.31), synovium thickness (r=0.28), hsCRP (r=0.44), HbA1c (r=0.45), cholesterol (r=0.29), LDL (0.3), triglycerides (r=0.36), uric acid (r=0.3), leptin (r=0.46), IL-6 (r=0.38), COMP (r=0.51). Negative correlations (p &lt;0.05) were established with medial joint space (via X-ray): (r=-0.24) and cartilage thickness (via ultrasound) (r=-0.25). Conclusion Comprehensive examination of patients with the use of imaging and biochemical methods showed that metabolic phenotype of osteoarthritis is more severe (with correction for age taken into account). Patients with metabolic phenotype showed higher levels of hsCRP, leptin, IL-6, COMP, which possibly demonstrate a more active form of low-grade inflammation (the underlying mechanism of OA pathogenesis) and more significant cartilage damage Disclosure of Interests None declared